tangoGPS is an easy to use, fast and lightweight mapping application for use with or without GPS. it runs on any Linux platform from the desktop over eeePC down to phones like the Openmoko Neo. By default tangoGPS uses map data from the Openstreetmap project. Additionally a variety of other repositories can be easily added.
The maps are automagically downloaded and cached for offline use while you drag or zoom the map. Furthermore you can conveniently pre-cache areas with tangoGPS.
If connected to a GPS your current position and track are shown on the map and you can log positional data for further processing, i.e. for geocoding photos or uploading streets to Openstreetmap.
Geocoded images can be shown with the correct position on the map and you can mark your favourite locations and any points of interest on the map.
Last not least a friend finder function lets you exchange your position with others and you can send messages
Routes can be fetched from teh web in GPX format.